(a) Field of the Invention
The present invention relates to a vibration control apparatus of a driving system for a vehicle and a control method thereof. More particularly, the present invention relates to a vibration control apparatus of a driving system for a vehicle and a control method thereof using the speed of a motor.
(b) Description of the Related Art
Generally, a hybrid vehicle uses an engine and a motor as alternating or supplemental power sources for reducing emissions and improving fuel consumption efficiency. In addition, hybrid vehicles can be divided in to three distinct types: a power split type, a soft type and a transmission-mounted electric drive (TMED) type.
Hybrid vehicles using the TMED type include an engine, an ignition starting generator (ISG) connected with the engine by a pulley so as to increase speed of the engine when the engine is started, a clutch to engage and disengage power from the engine to the transmission and output shaft, and a drive motor directly connected with a transmission. Typically, a continuously variable transmission (CVT) or a multi-stage shifting transmission is used as the transmission of the hybrid vehicle. In particular, a multi-stage shifting transmission is generally installed in a TMED type hybrid vehicle.
When the supply of engine torque is required in the TMED type hybrid vehicle, impact and vibration can occur due to engagement of the clutch as engine torque is being applied. Thus, a multi-stage shifting transmission may be more disadvantageous than a CVT with regard to the level of smoothness felt during shifting.
Conventionally speaking, a typical automatic transmission includes a torque converter disposed between an engine and a transmission for absorbing shock related to power delivery and shifting. However, a TMED type hybrid vehicle utilizes a wet clutch instead of a torque converter to absorb the shock form the power delivery and thus can feel “clunky” to the user.
In addition, a transmission, a reduction gear and various gear elements disposed between a motor and a drive shaft of the hybrid vehicle have a backlash characteristic. However, in a hybrid vehicle vibration is generated when the direction of torque is switched due to the gear elements since the hybrid vehicle lacks damping elements such as a torsion damper to account for the backlash of the gear elements. Further, the vibration may induce deterioration in drivability of the vehicle.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.